The purpose of this study is to study the potential benefits of low fat vegan diet in a randomized, controlled and multi-centered workplace setting, the investigators will enroll participants from 10 worksites of Government Employee Insurance Company (GEICO). After randomization, 5 will be the vegan sites and 5 will be the control sites for 10 month study. The vegan sites will receive low fat vegan diet instructions and weekly group sessions starting from year 1. no intervention is done to the control sites until the week 18 when the identical program will be given. At various time points, health measurements will be give to all participants.